河西走廊中部沙漠植物δ^(13)C值的特点及其对水分利用效率的指示

Characteristics of δ^(13) C Values of Desert Plants and Their Water Utilization Efficiency Indicated by δ^(13) C Values in the Desert of Central Hexi Corridor Region

通过分析河西走廊中部沙漠中几种木本植物叶片或同化枝的稳定碳同位素比率(δ13C)和碳同位素辨别力(Δ),以其作为水分利用效率(WUE)的指示,研究了本区沙漠植物叶片或同化枝δ13C值的季节变化特点,以及不同生境和不同水分状况下δ13C值的差异,并比较研究了绿洲防护林树种及绿洲作物.结果表明:梭梭和沙拐枣同化枝的δ13C值分别为-14 31‰和-14 82‰,Δ值在5‰～6‰之间;柠条、泡泡刺、花棒和红沙叶片的δ13C值分别为-25 75‰、-25 79‰、-26 38‰和-28 05‰,Δ值在16‰～20‰之间.几种沙漠植物长期水分利用效率大小的顺序为:梭梭≈沙拐枣>柠条≈泡泡刺≈花棒>红沙.

Temperate desert plants always grow in the high temperature, arid and water deficit environment throughout a year. Different plants have different photosynthetic organs to adapt extreme environmental conditions. The purpose of this paper is to probe into the characteristics of\{δ 13 C\} of leaves and assimilating shoots and into water use efficiency (WUE) of desert plants, and to provide a theoretical basic for protecting and fostering natural ecosystems of desert regions. The results achieved by the present study will serve restoring the degraded vegetation and maintaining the stability of protective eco\|systems in the peripheric districts of oases. The\{δ 13 C\} values of leaves and assimilating shoots of desert plants in the desert of central Hexi Corridor region (39°19′～39°21′ N, 100°02′～100°21′ E, \{1 368\}～\{1 380\} m a.s.l.) were analyzed and discussed in this paper. \{δ 13 C\} of leaves and assimilating shoots and \{δ 13 C\} air were analysed with MAT\|252 mass spectrometer. The characteristics of\{δ 13 C\} of leaves or assimilating shoots and WUE of plants indicated by\{δ 13 C\} values in this region were also studied. At the same time, comparative studies of shelterbelt arborous species and some oasis crops were also carried out. The results indicate that the \{δ 13 C\} values of assimilating shoots of \%Haloxylon ammodendron\% and \%Calligonum mongolicum\% are \{-14.31‰\} and \{-14.8‰\} respectively, and stable carbon isotope discrimination (\%Δ\%) is between 5‰～6‰. The \{δ 13 C\} values of leaves for \%Caragana korshinskii, Nitraria sphaerocarpa, Hedysarum scoparium\% and \%Reaumuria soongorica\% are \{-25.75‰\}, \{-25.79‰\}, \{-26.38‰\} and \{-28.05‰\} respectively, while \%Δ\% is between 16‰～20‰.\;The long\|term water use efficiency of several desert plant species can be ranked in the general order: \%H. ammodendron≈C. mongolicum>C. korshinskii≈N. sphaerocarpa≈H. \{scoparium\}>R. soongorica\%.